Packaging machine and method for supplying containers in a packaging machine

ABSTRACT

A packaging machine is described having a grouping device for grouping containers comprising a supply device ( 2 ) which consecutively with a predetermined speed supplies containers ( 5 ) to a working station ( 20 ) and a grouping device ( 6   a - 6   d,    60   a - 60   d ) grouping containers on the supply device ( 2 ). The grouping device comprises a sensor element ( 70 ) for detecting the supply of a container ( 5 ) and at least two stopper elements ( 6   a - 6   d,    60   a - 60   d ) which are, for stopping the motion of subsequent containers, successively moved at a time which is determined from the time of detection of the supply of a container ( 5 ) and from the speed of the supply device ( 2 ), while the supply device ( 2 ) keeps on supplying containers ( 5 ).

The present invention relates to a packaging machine and to a method for supplying containers in a packaging machine.

Packaging machines, so-called tray closing machines, are known in which products are packaged into pre-fabricated tray-shaped containers and closed with a film.

From DE 690 03 503 a packaging machine is known in which the packaging containers are transported from a filling station onto a plate in a sealing station by means of circulating drivers. It is disadvantageous that the positioning of the containers takes place in a very imprecise way and takes a lot of time since the acceleration must remain low and the drivers must return from the region of the sealing station.

From EP 680 880 a machine is known in which the containers are directly transported into a closing device (sealing station) from a supply unit by pusher arms and, at the same time, the closed containers are removed from the closing device. Here as well, the containers are positioned on plates in the sealing station and the positioning is imprecise and the transport takes a lot of time. Furthermore, detectors are disclosed which detect the containers during supply, and the movement of a conveyor belt is controlled based on the detection.

It is disadvantageous in these packaging machines that no fast and precise positioning of containers in a working station of the packaging machine can be performed and that a changeover to different container sizes and geometries is complicated.

In EP 0 959 028 A2 a grouping device in an accumulation conveyor track is described. On the accumulation conveyor track containers are stopped in an accumulation region with a distance relative to each other and, for the individual stopping positions, separate sensors are provided. The grouping device is formed for a fixed container size and a fixed distance of the containers, respectively, and a changeover to other container sizes and distances, respectively, demands a large effort.

From U.S. Pat. No. 1,367,081 a track is known which serves for supplying containers to an elevator. With this track, containers in direct succession are spaced from each other. A secure and precise grouping is not allowed for.

It is the object of the present invention to create a packaging machine which allows to group containers securely with high speed and to supply the containers to a subsequent working station and, at the same time, ensures an easy changeover of the packaging machine to different container sizes and geometries, and to provide a method permitting these advantages.

The object is attained by a packaging machine according to claim 1 and by a method according to claim 7. Further developments of the invention are specified in the subordinated claims.

The packaging machine according to the invention has the advantage that the grouping and the transport of the containers to the working station can be performed very fast. Furthermore, an exact positioning of the containers is achieved.

It is a further advantage of the present invention that the packaging machine can be changed over to different container sizes and shapes very easily and that in particular for only different container height no changeover is necessary.

Furthermore, due to the continuously running supply device, a complicated fixed-cycle operation of the supply device which is necessary in a supply device working intermittently can be omitted in the packaging machine according to the invention.

Further features and advantages of the invention will arise from the description of embodiments with reference to the enclosed figures. The figures show:

FIG. 1 a schematic top view of a packaging machine according to one embodiment of the present invention;

FIG. 2 a schematic side view of a packaging machine according to the first embodiment;

FIG. 3 an enlarged partial top view of the packaging machine of FIG. 2;

FIG. 4 a top view of a packaging machine according to a second embodiment in a first step of operation;

FIG. 5 a top view of the packaging machine of FIG. 4 in a second step of operation;

FIG. 6 a top view of the packaging machine of FIG. 4 in a third step of operation.

FIRST EMBODIMENT

In the following a first embodiment of the present invention will be described with reference to FIGS. 1 to 3.

As shown in FIGS. 1 and 2, the packaging machine of this embodiment includes a first supply conveyor belt 1 on which containers 5 to be closed are transported in a direction towards a closing station 20, a second supply conveyor belt 2 which is arranged in the input region of the closing station 20 and on which the containers 5 are grouped, and a removal conveyor belt 11 on which the containers 5″ are transported on after being processed in the closing station 20. The closing station 20 is formed such that a set of containers 5 can be processed simultaneously.

Via the first supply conveyor belt 1, the second supply conveyor belt 2 and the removal conveyor belt 11 the containers move in a main transport direction 8 which is indicated by an arrow in FIG. 2 and runs from the left to the right. The supply conveyor belts 1, 2 each run continuously and the grouping of the containers is performed by a plurality of stoppers 6 a to 6 d arranged above the second supply conveyor belt 2.

The first stopper 6 a which is located closest to the closing station 20 is arranged such that it stops a container 5 which is moved on the second supply conveyor belt 2 in the main transport direction 8, while the second supply conveyor belt moves on underneath it. The other stoppers 6 b, 6 c, 6 d are formed such that they can separately be moved from an elevated position in which the containers 5 on the second supply conveyor belt 2 can be transported underneath into a lowered position in which they stop containers 5 transported on the second supply conveyor belt 2 in the main transport direction 8 while the second supply conveyor belt 2 moves on underneath. Further, the stoppers 6 are formed such that they can be reciprocated in the main transport direction 8 by a control device which is not shown (29). As shown in FIG. 2 and FIG. 3, in the first embodiment the stoppers 6 a-6 d are formed by plates which protrude above the second supply conveyor belt 2 from above and extend in perpendicular to the main transport direction 8. The stopping of the containers 5 transported on the second supply conveyor belt 2 is effected in that the containers 5 in their motion abut onto the stoppers 6 a-6 d with their front edge 5 f and, thus, are held by them.

Furthermore, a sensor 70 which detects the transport of a container 5 from the first supply conveyor belt 1 to the second supply conveyor belt 2 is provided on the input side of the second supply conveyor belt 2 in the main transport direction 8. Based on the detection time of an approaching container 5 and on the known transport speed of the second supply conveyor belt 2 which is continuously and uniformly transporting in the direction towards the closing device 20, the time at which the subsequent stopper 6 b-6 d has to be moved into the main transport path is determined by the above mentioned control device.

As shown in FIG. 3, guide plates 40 are arranged laterally above the second supply conveyor belt 2 for lateral alignment of the containers 5 in the direction perpendicular to the main transport direction 8.

A site referred to as a first position 21 for a receiving plate 3 is located in the closing station 20 behind the second supply conveyor belt 2 in the main transport path. In the first position 21, the receiving plate 3 is arranged such that the containers 5 stopped on the second supply conveyor belt 2 by the stoppers 6 a-6 d can be shifted above the receiving plate 3 by a movement of the lowered stoppers 6 a-6 d in the main transport direction 8. Inside the receiving plate 3 recesses 10 are provided into which the containers 5 which are shifted above the receiving plate 3 can be lowered by means of a lifting device 9 provided below the receiving plate 3. Then, the lowered containers 5 are held at the upper container rim 5 e by the receiving plate 3. A number of recesses 10 which corresponds at least to the number of containers 5 per set are provided in the receiving plate 3. It is also possible to simply drop the containers 5 into the recesses 10 without making use of the lifting device 9.

In the first position 21, sealed containers 5″ can be lifted up in the recesses 10 of the receiving plate 3 by means of the lifting device 9 such that the container bottoms 5 a are aligned with the upper side 3 a of the receiving plate 3 located in the first position 21. A pusher 7 is provided which is formed by drivers 7 a protruding from above which are formed such that they reach between the sealed containers 5″ in a first position, as illustrated in FIG. 2. By shifting the pusher 7 in the direction of the main transport direction 8 into a second position (right end of arrow 30 in FIG. 2), the sealed containers 5″ are shifted onto the removal conveyer belt 11.

In the following the closing station 20 is described more detailed. As shown in FIG. 4, a second receiving plate 3′ having recesses 10′ and formed identical to the receiving plate 3 is located in the closing station 20 at a site referred to as second position 22. The second position 22 is located laterally of the main transport direction 8 and further up than the first position 21.

A transport mechanism is provided which is not shown and with which the receiving plates 3, 3′ can be moved from the first position 21 via a second intermediate position into the second position 22 and from the second position 22 via a first intermediate position into the first position 21, respectively. This motion from the first position 21 into the second position 22 and back, respectively, is realised by two consecutive linear motions each.

When in the second position 22, the receiving plate 3′ is located in-between an upper part and a lower part of a closing device which is not shown in detail. The lower part can be moved upward by means of a lifting device such that the lower part together with the upper part and the receiving plate 3′ pressed therebetween forms a closed chamber. Devices allowing for an evacuating and a supply of gas such as an inert gas are provided at this closing device.

An upper film is arranged in the region of the closing device such that a portion of the upper film is sandwiched between the upper part and the receiving plate 3′ when the closing device is closed, with the result that this portion comes to rest on the upper container rims 5 e of the containers 5′ held in the recesses 10′ of the receiving plate 3′.

The upper side of the receiving plate 3′ and the upper part are formed such that they form a sealing and cutting tool sealing the upper film onto the upper container rims 5 e and in doing so cutting free the sealed region from the upper film. Furthermore, the closing device is formed such that it opens again after the sealing of the containers 5′ and a following portion of the upper film is moved into the closing device.

In the following, the operation of the packaging machine of this embodiment is described with reference to FIGS. 1 to 3. During operation, irregularly spaced containers 5 are transported on the first supply conveyor belt 1 in the direction towards the second supply conveyor belt 2. The containers 5 are already filled with products to be packaged. The filling may be performed on the first supply conveyor belt 1 or even before it. The containers 5 are transferred from the first supply conveyor belt 1 to the second supply conveyor belt 2. At this time, the respective containers 5 are detected by the sensor 70 which is provided on the second supply conveyor belt 2 on the input side.

The first container 5 b is transported on the second supply conveyor belt 2 in the main transport direction 8 until it abuts onto the first stopper 6 a which inhibits the continuation of its motion and, during this, is guided by the guide plates 40 in its lateral alignment in the direction perpendicular to the main transport direction 8. The second supply conveyor belt 2 moves on underneath the held first container 5 b. Then, the following stopper 6 b moves down behind the first container. The moment of the downward movement is determined by the control device based on the moment at which the sensor 70 detects the transport of a container 5 from the first supply conveyor belt 1 to the second supply conveyor belt 2 and on the transport speed of the second supply conveyor belt 2.

Coming from the first supply conveyor belt 1, the following container 5 c is moved with the second supply conveyor belt 2 in the main transport direction 8 until it abuts onto the stopper 6 b. Thereafter, the following stopper 6 c is moved down at a time in accordance with the detecting by the sensor 70 and with the transport speed of the second supply conveyor belt 2, and the procedure recurs until a pre-set number of containers 5 are grouped. A number of three containers per set are shown in FIGS. 1 to 3 each but another number may be realised as well. The distance relative to each other of the containers 5 of one set is set by the distance of the stoppers relative to each other.

Afterwards, the stoppers 6 a-6 d are moved in the main transport direction 8 (arrow 29 to the right) and the grouped containers 5 are moved above a receiving plate 3 located in the position 21. At the same time, sealed containers 5″ located on the receiving plate 3 are moved onto the removal conveyor belt 11 by the pusher 7. The grouped containers 5 which were moved above the receiving plate 3 are lowered into the recesses 10 of the receiving plate 3 by the lifting device 9 or dropped into the recesses without making use of the lifting device 9 and then held therein by the upper rim 5 e of the containers 5. During the time when the sealed containers 5″ are moved onto the removal conveyor belt 11 by the pusher and the grouped containers 5 are moved into the recesses 10 of the receiving plate 3, containers 5′ which are located on the receiving plate 3′ are sealed in the closing device 25.

After the sealing process in the closing device 25 is completed and the containers 5 to be closed have been placed in the recesses 10 of the receiving plate 3 which is located in the first position 21, the closing device 25 is opened by lowering the lower part 24 with a lifting device which is not shown. Thereafter, the receiving plate 3′ is linearly lowered in the vertical direction into a first intermediate position having the height of the first position 21 from the second position 22 which is arranged laterally of the main transporting direction 8 and higher than the first position 21. At the same time, the other receiving plate 3 is linearly lifted up in the vertical direction from the first position 21 into a second intermediate position. Thereafter, the receiving plate 3′ containing sealed containers 5″ is linearly moved in the horizontal direction from the first intermediate position into the first position 21. At the same time, the receiving plate 3 with the unsealed containers 5 is linearly moved in the horizontal direction from the second intermediate position into the second position 22 in the closing device 25 such that the receiving plates 3, 3′ have interchanged their positions.

Subsequently the closing device 25 is closed and the containers 5′ on the receiving plate 3 located therein are sealed with the upper film and, thereafter, the closing device opens again. At the same time, the sealed containers 5″ in the receiving plate 3′ in the first position 21 are lifted up with the lifting device 9 and moved onto the removal conveyor belt 11 by the pusher 7, while containers 5 which were in the meantime grouped on the second supply conveyor belt 2 are moved above the receiving plate 3′ by the stoppers 6 a-6 d and are subsequently lowered into the recesses 10′ of the receiving plate 3′ by means of the lifting device 9 or simply dropped into the same.

When the sealing process in the closing device 25 is finished and the following grouped containers 5 were placed in the recesses 10′, the receiving plate 3′ is moved from the first position 21 via the second intermediate position into the second position 22 and, at the same time, the other receiving plate 3 is moved from the second position 22 via the first intermediate position into the first position 21. Subsequently, the described procedures recur with the result that further containers 5 are successively sealed.

SECOND EMBODIMENT

In the following, a second embodiment of the present invention is described with reference to FIGS. 4 to 6.

As illustrated in FIGS. 4 to 6, the second embodiment of the present invention differs from the first embodiment shown in FIGS. 2 and 3 in the construction of the stoppers only. The other components correspond to those of the first embodiment and, therefore, will not be described again. In particular, identical reference numerals are used for identical components.

Instead of the stoppers 6 a-6 d stoppers 60 a-60 d are provided in the second embodiment. The arrangement of the stopper 60 a corresponds to that of stopper 6 a, and the stoppers 60 b-60 d differ from stoppers 6 b-6 d in that; they reach into the main transport path of the containers 5 which are transported on the second supply conveyor belt 2 from the side and, at the same time, perform the function of the guide plates 40 of the first embodiment. The stoppers 60 b-60 d are each formed as two vertical plates which extend laterally in parallel to the second supply conveyor belt 2 and which comprise portions 60 b′-60 d′ projecting in the direction of the main transport path of the containers 5. The stoppers 60 b-60 d are horizontally movable in the direction perpendicular to the main transport direction 8 by laterally arranged control devices 61 b-61 d.

The operation of the grouping device of the second embodiment is now described with reference to FIGS. 4 to 6. As illustrated in FIG. 4, first a first container 5 b moves in the main transport direction 8 on the second supply conveyor belt 2 passing in between the stoppers 60 b-60 d which are moved to the outside until it abuts onto the first stopper 60 a, and is then held there while the second supply conveyor belt 2 moves on underneath it. Thereafter, the plates of the second stopper 60 b move to the inside above the second supply conveyor belt 2 and, in doing so, centre the first container 5 b in the lateral direction perpendicular to the main transport direction 8. As in the first embodiment, the timing of the movement to the inside is determined based on the time of detection of a container 5 by the sensor 70 and on the transport speed of the second supply conveyor belt 2. Then, the projecting portions 60 b′ of the second stopper project above the second supply conveyor belt 2 and a second container 5 c which is subsequently transported on the second supply conveyor belt 2 is stopped by the projecting portions 60 b′ while the second supply conveyor belt moves on underneath it. Afterwards, the two plates of the third stopper 60 c are moved to the inside above the second supply conveyor belt 2 at a timing which is determined in accordance with the detection of a container by the sensor 70 and with the transport speed of the second supply conveyor belt 2 and, during this, the second container 5 c is centred in the direction perpendicular to the main transport direction 8.

This procedure recurs until a pre-set number of containers 5 which form one set are reached. In the embodiment illustrated in FIGS. 4 to 6, three containers form a set but more or less are possible as well. As shown in FIG. 6, subsequently the whole group is moved onto the receiving plate 3 by the stoppers 60 a-60 d and the stoppers 60 b-60 d are driven to the outside again. Subsequently, all stoppers 60 a-60 d are moved back into their position above the second supply conveyor belt 2.

Then, the further operation in the second embodiment corresponds to that of the first embodiment again.

In the described embodiments it is of course also possible to combine more containers or less to a set. In particular with a stopper device formed similar to the first embodiment, plural containers can be grouped side by side.

Other different shapes are also possible for the shape of the single stopper elements.

It is in particular advantageous that an easy changeover to different container sizes and shapes is possible. If, for example, only containers of different height shall be used, then, no changeover is necessary since the stopper elements 6 a-6 d and 60 a-60 d, respectively, are formed by elements projecting above the second supply conveyor belt 2 from above or laterally which do not have to be adapted to special shapes or sizes of the containers, and since further the containers 5, 5′, 5″ are held in the recesses 10, 10′ with their upper rim 5 e, having the result that the height of the flange region in which the sealing is performed is unaltered in the positioning in the closing device 25. If the packaging machine shall be changed over to another shape of containers, then only the receiving plates 3, 3′ and the upper part 23 of the closing device 25 have to be substituted in the first embodiment and the lower part 24 of the closing device as well as the stopper elements 6 a-6 d can be maintained. Thus, a very easy and cost-efficient changeover to different container sizes and shapes can be carried out. When the width of the containers 5 shall be changed in a wider range, the distance of the stopper elements relative to each other can easily be changed without altering the stopper elements themselves.

Though in the described embodiments the succeeding working station is described as a closing station (20) in which the closing device (25) is arranged laterally of the main transport path, also a closing device which is arranged in the main transport path can be used. The working station is not restricted to a closing station but may also be another working station which is used in the packaging machine; it may be a cutting or punching device or something similar as well, for example. 

1. A packaging machine with a grouping device for grouping containers, comprising: a supply device which supplies containers consecutively with a predetermined speed to a working station; and a grouping device grouping containers on the supply device, wherein the grouping device comprises: a sensor element for detecting the supply of the respective containers; a first stopper element for stopping the motion of a first container; and at least a second stopper element for stopping the motion of a subsequent container, moved at a time which is determined from the time of detection of the supply of a container and from the speed of the supply device, while the supply device keeps on supplying containers.
 2. A packaging machine according to claim 1, wherein the supply device is a conveyor belt running continuously.
 3. A packaging machine according to claim 1, wherein the stopper elements are adjustable such that the containers have a pre-determinable distance relative to each other after grouping.
 4. A packaging machine according to claim 1, wherein the stopper elements reach into the motion of the containers on the supply device from above or laterally.
 5. A packaging machine according to claim 1, wherein the stopper elements are collectively movable in the direction towards the working station for transporting grouped containers to the working station.
 6. A packaging machine according to claim 1, wherein the second stopper element is moved behind the first container.
 7. A method for grouping containers in a packaging machine comprising the steps: a) consecutively supplying containers in a direction towards a working station with a predetermined speed and detecting the supply of the respective containers with a sensor element; b) stopping a first container with a first stopper element while the supply device keeps on supplying containers; and c) introducing a second stopper element into the direction of movement of the containers behind the first container at a time which is determined from the time of detection of the supply of a container and from the supply speed.
 8. The method according to claim 7, further comprising the step of stopping a second container at the second stopper element while the supply device keeps on supplying containers. 